Disk drives include a disk which stores information, a spindle motor that rotates the disk, a head that reads from and writes to concentric tracks on the disk, and an actuator arm assembly that supports the head over the disk and radially positions the head relative to the disk.
Disk drives receive access requests (read requests and write requests) from a host computer that uses the disk drive as a mass storage device. Access requests that require the head to move to another track include seek requests. The head is moved from a start track to a destination track where a desired data sector resides during a seek operation. Thereafter, the head is maintained over the destination track by reading servo information from the destination track during a track following operation, and the disk rotation places the head over the data sector so that the head can access the data sector. The head reads data from the data sector during a read operation, and writes data to the data sector during a write operation. The access time for accessing the data sector includes the seek time for performing the seek operation, the settle time for establishing the track following operation, and the rotational latency time for the disk rotation to place the head over the data sector.
Disk drives are expected to provide increasing higher data transfer rates, which in turn require increasingly lower access times. As a result, disk drives require increasingly higher seek speeds with lower seek times.
Disk drives emit acoustics during disk rotation and seek operations. Unfortunately, disk rotation acoustics and seek acoustics are undesired noise that can bother the end user and disrupt other devices. This creates a tradeoff between seek speed and seek acoustics. Increasing the seek speed increases the seek acoustics, thereby increasing the data transfer rate but creating more noise, whereas decreasing the seek speed decreases the seek acoustics, thereby creating less noise but decreasing the data transfer rate.
Disk drives have been designed to provide different combinations of seek speed and seek acoustics. For instance, a disk drive includes a first servo configuration page for low seek speed and low seek acoustics (“quiet mode”), and a second servo configuration page for high seek speed and high seek acoustics (“fast mode”). The host computer selects between the quiet mode and the fast mode, depending on which mode is best suited for a particular application. For instance, a video playback system may prefer the quiet mode, whereas a personal computer may prefer the fast mode. However, the disk drive is incapable of assisting the host computer with determining which mode should be employed. Instead, the host computer is burdened with selecting the seek speed and seek acoustics and conveying the selection to the disk drive.
Therefore, there is a need for a disk drive that balances seek speed and seek acoustics.